I. Field
The following description relates generally to wireless communications, and, amongst other things, to flexible communication schemes for wireless communication systems.
II. Background
Wireless networking systems have become a prevalent means by which a majority of people worldwide has come to communicate. Wireless communication devices have become smaller and more powerful in order to meet consumer needs and to improve portability and convenience. Consumers have found many uses for wireless communication devices such as cellular telephones, personal digital assistants (PDAs) and the like, demanding reliable service and expanded areas of coverage.
Performance for a wireless communication system may be enhanced by using beamformed transmissions to communicate from the base station to the mobile devices. Multiple transmit antennas located at a base station can be used to form beamformed transmissions. Beamformed transmissions utilize “beams” that typically cover a narrower area than transmissions using a single transmit antenna. However, the signal to interference and noise ratio (SINR) is enhanced within the area covered by the beams. The portions of a sector not covered by a beam are referred to as a null region. Mobile devices located within the null region will have will have an extremely low SINR, resulting in reduced performance and possible loss of data. The communication system may use beam steering, in which beams are dynamically directed at particular user devices. During beam steering, beams are redirected as user devices change location.
A typical wireless communication network (e.g., employing frequency, time, and code division techniques) includes one or more base stations that provide a coverage area and one or more mobile (e.g., wireless) user devices that can transmit and receive data within the coverage area. A typical base station can simultaneously transmit multiple data streams for broadcast, multicast, and/or unicast services, wherein a data stream is a stream of data that can be of independent reception interest to a user device. A user device within the coverage area of that base station can be interested in receiving one, more than one or all the data streams carried by the composite stream. Likewise, a user device can transmit data to the base station or another user device. Such communication between base station and user device or between user devices can be degraded due to channel variations and/or interference power variations. For example, the aforementioned variations can affect base station scheduling, power control and/or rate prediction for one or more user devices.
Conventional network fixed beamformed transmissions result in null regions, reducing network reliability, robustness and coverage area. Thus, there exists a need in the art for a system and/or methodology for improved beamformed transmission coverage.